The gerund does not express any timeA concept which is related to our perception of reality; that part of existence which is measured in seconds, minutes, hours, days, weeks, etc. in itself, however it can show whether the actionA general term expressing that somebody or something does something expressed with it happened or happens earlier or not than something else in the sentence. We call this "something else" a time markerA verb or auxiliary that marks the reference point of a non-finite form. E.g.: The telephone is known to have been invented by Bell. ("is") He denied being in love with the suspect. ("denied") He must have arrived late. ("must").

Non-finite forms of a verbA part of speech that expresses an action or a state. E.g.: John seldom plays tennis. do not indicate the timeA concept which is related to our perception of reality; that part of existence which is measured in seconds, minutes, hours, days, weeks, etc. of the actionA general term expressing that somebody or something does something, however, they do have aspectA verbal category relating an action to the passage of time. It can express duration or completion..